4 ideas
In 1346 a Mongol army under Janibeg besieged the Genoese trading colony of Caffa in Crimea. According to the notary Gabriele de' Mussi, the Mongols catapulted plague-infected corpses over the walls. Genoese ships fleeing the city then carried the disease into the Mediterranean, reaching Messina in October 1347 and opening the European epidemic.
The Black Death was so lethal partly because Europe was already stressed before the bacillus arrived. Population had outgrown the land, and the Great Famine of 1315–22 and a cooling climate had left a generation malnourished and immunologically weak. Dense, filthy towns full of rats and fleas then gave the pathogen ideal conditions, so mortality depended as much on this prior fragility as on the pathogen itself.
In February 1349, before plague had even reached Strasbourg, the town's Jews were accused of poisoning wells, and hundreds were burned in their cemetery. The debts owed to them were cancelled and their property was divided among the townspeople. This happened even though Pope Clement VI had issued bulls pointing out that Jews were dying of plague too.
Plague killed roughly a third or more of Europe's population, which made surviving workers scarce and let them demand higher wages and better terms. Elites tried to freeze wages by law, as with England's Ordinance and Statute of Labourers of 1349–51, but the shortage steadily undermined the old manorial order.